In recent years, there has been an increasing demand for high resolution and high quality video such as High Definition (HD) video and Ultra High Definition (UHD) video in various fields. The data amount of the image data increases in order to provide a high-quality and high-resolution image. Therefore, compared with the existing image data processing method, the transmission cost and the storage cost of the image data for providing a high-resolution and high-quality image are increased. Therefore, high-efficiency image compression techniques can be utilized to solve such problems as image data come to have high-resolution and high-quality.
In the meantime, a conventional encoding/decoding technique based on H.264, HEVC, or the like is a technique of allocating sign information of a pixel including a non-zero transform coefficient of a transform coefficient block to one bit per pixel compression was performed. However, in case of the conventional art, the code information of the pixels including at least one non-zero transform coefficient selected in the transform coefficient block needs to be compressed and signaled to a decoding device and thus, there is a problem that the compression efficiency is low.
Therefore, we propose a solution to efficiently compress the sign (or differential motion vector) of the transform coefficients of each pixel having non-zero integer values in the transform coefficient block.